The overall objective of the Animal Core is to provide center investigators with the ability to utilize animal models in the execution of their proposed research projects, as well as, establish new animal models for the investigation of the mechanisms involved in the regulation of reproduction. The Center for Reproductive Research will utilize two animal models, mice and rats, in the execution of the research projects. Although the use of animal models provides an invaluable source of reagents for investigating regulatory mechanisms in vivo, in a physiologically regulated system, the use of animals in biomedical research is costly with respect to equipment, animal resources and technical expertise. The Animal Core will serve as a resource for the execution and training in the use of all animal manipulations needed in the Center. The Animal Core will minimize the cost of utilizing animal models in the Center Research Program by consolidating the equipment, expertise and animal resources. This will ensure an efficient use of animal research at minimal cost.